Where a backrest of a chair-type massage apparatus is concerned, there is a heretofore known a backrest which is internally provided with a massage device for imparting massage action to a pair of right and left massage members.
As a device of this type, there is proposed a back-kneading device equipped with an advancing-retracting system capable of driving a massage member to move forward beyond a normal massage position, as well as to return to its original position, to suit the needs or preferences of a user (for example, refer to Patent literature 1).
In this advancing-retracting system, a support frame, which is moved up and down within the backrest by a vertical movement mechanism, is provided independently of the massage device, and, the massage device is supported on the support frame so that the upper end of the massage device can be rocked back and forth about the lower part thereof acting as a pivotal point. Moreover, the mutually corresponding upper parts of the support frame and the massage device are driven to move close to and away from each other in a front-rear direction (back-and-forth driving).